The biggest benefit is that it increases your vote value, so when you upvote a post or comment you like both you and the person you're upvoting will earn more from it.
It makes it easier to get over the 2 cent dust threshold, as well - where a post or comment needs to earn more than 2 cents in total from all it's votes.
Also, it increases the value of any votes for witnesses and proposals you do, and your resource credits (the number of actions/transactions) you can do. Both vote value and resource credits regenerate after being used - about 20% comes back each day.